Promising In Vitro Anti-Toxoplasma gondii Effects of Commercial Chitosan

Background: Toxoplasmosis is a disease that results from infection with an obligate intracellular T. gondii parasite, one of the world's most common parasites. Considering the complications of chemical drugs and the need for an appropriate drug combination for treatment of toxoplasmosis and considering the antimicrobial potential of chitosan, as a natural source, this study was aimed to evaluate in vitro activity of commercial chitosan (CC) on T. gondii. Methods: In this experimental study, the tachyzoites of T. gondii were collected from the peritoneal exudates from infected Balb/c mice. The tachyzoites were diluted in phosphate buffer saline (PBS) solution. Chitosan with low molecular weight was commercially purchased. Then, at concentrations of 10, 50, 100, and 200 μg/mL and after 30, 60, 120, and 180 minutes, the viability of tachyzoites was determined by using trypan blue 0.1%. Anti-T.gondii activity of CC in all concentrations was significantly higher than pyrimethamine as the control group (P=0.05). Results: The concentration of 200 μg/mL of CC had the highest effects and killed 30.5, 52, 59, and 81.5% of tachyzoites after 30, 60, 120, and 180 minutes. Moreover, IC50 values of CC were 515, 171, 12.5, and <10 μg/mL in comparison with pyrimethamine as 58.82 μg/mL for 30, 60, 120, and 180 min of exposure time. Conclusion: Our results indicate that chitosan in low molecular weight had potent activity against T. gondii tachyzoites and could be an appropriate candidate for the treatment of at least acute toxoplasmosis, certainly, after complementary in vivo experiments.